A squib valve is a single action valve used for permitting rapid exit of a fluid from a pressurized fluid source. Squib valves are used to permit evacuation of a fluid stored under pressure. Typically, although not exclusively, squib valves are used to permit rapid release of fluids retained under a wide range of pressures, typically 1,000-10,000 psi. Squib valves are used, for example, in aircraft ejector mechanisms, missile firing mechanisms, missile fuel supply systems and fire extinguishing systems.
Among problems that exist with conventional squib valves are the occurrence of shock and hammering downstream of the valves. The shock and hammering are caused by the sudden, uncontrolled release of pressurized fluid, wherein an outflow from a squib valve increases, almost instantaneously, from a zero flow rate to a maximum flow rate. This problem is particularly acute with highly pressurized fluids.
Conventionally, squib valves are one-shot devices, and employ a "guillotine-type" or "penetration-type" action for forming a fluid outlet. A problem with both these types of squib valves is that the cutting or piercing action by which the fluid outlet is formed causes particles of the material which formerly covered the outlet to be released into the fluid flow. These particles are essentially contaminant particles. Accordingly, these prior art squib valves are not suitable for use with an ultra-high purity gas supply without a suitable filtration system.
Furthermore, due to the high cost of squib valves, it would be desirable to provide a squib valve that is re-usable, especially when being used in ground applications and qualification tests, for example.